INTRAOPERATIVE RADIOTHERAPY OF CANINE BLADDER CANCER

Abstract

Thirteen dogs had partial surgical extirpation followed by whole bladder intraoperative radiotherapy for urinary bladder cancer. Eleven of the neoplasms were transitional cell carcinomas (five Stage T1, six stage T2); one was rhabdomyosarcoma (Stage T2), and one was leiomyosarcoma (Stage T2). Histopathologic evaluation showed that neoplasia extended to the margins of the excised tissue in at least 11 of the 13 dogs. Radiotherapy from a 137Cs teletherapy machine was applied to the surgically exteriorized bladder, with doses at the 90% isodose level varying from 2188 to 2888 cGy (10 of 13 dogs receiving 2670–2700 cGy). Sixty‐one percent of the dogs were alive at 1 year, 30% at 18 months, and 15% at 2 years. From the time of initial clinical signs of bladder neoplasia, 69% of the irradiated dogs were alive at 1 year, 46% at 18 months, and 23% at 2 years (one dog is still living, at 70 months). Of the owner‐reported or clinically determined posttherapy complications, there was increased frequency of urination in 46% of the dogs, urinary incontinence in 46%, cystitis in 38%, and stranguria in 15%. Either persistence or recurrence of neoplasia was found in six (46%) of the dogs and metastasis in four (30%), with two of these having both recurrence and metastasis. Qualitative assessment of the complications was not done, but owner‐perceived severity of the complications, metastasis, or diagnosed persistence or recurrence of the neoplasm were the major reasons for ultimately killing most of the dogs.